There continues to be a need for treatments for all types of wounds, including wounds created as part of a surgical procedure. In particular, when the injury involves the removal of tissue, thereby leaving a void in the tissue, it is frequently desirable to replace that removed tissue with a surrogate that will function structurally like the removed tissue, and ideally aid in regrowth of new healthy tissue during the healing process.
Examples of non-surgical wounds include battle wounds and wounds sustained in accidental injury and trauma. Examples of surgical wounds include wounds resulting from the removal of tumors, both cancerous and non-cancerous. One particular type of surgical cancer wound is a wound resulting from a lumpectomy, a procedure frequently performed in the treatment of breast cancer.
In 2010, over 209,000 new breast cancer cases were diagnosed in the United States, and a further 68,000 new Ductal Carcinoma In Situ (DCIS) cases were reported. DCIS is a type of mammary ductal carcinoma. Approximately 70% of these new cases were treated with breast conserving therapy (BCT), which generally consists of lumpectomy followed by radiation therapy. The radiation can be delivered to the entire breast (whole breast irradiation plus lumpectomy boost) or just to the lumpectomy cavity (Accelerated Partial Breast Irradiation, or APBI). APBI is frequently chosen as the front line treatment. Two modes of APBI are currently available, device-based and external beam radiation therapy (EBRT). Device-based therapy involves inserting a device into the lumpectomy cavity and is therefore not only invasive, but requires specialized physician expertise. Device-based APBI provides more conformal treatment than is possible with EBRT; that is, it is more focused and more conformed to the cavity, including the tissue that was previously in immediate contact with the removed breast lesion. In contrast EBRT is less focused and treats larger volumes, but has the advantages of being non-invasive (external beam) and requiring minimal additional physician training or expertise. Furthermore, even in the whole breast irradiation scenario, it is very common to deliver a boost dose to the lumpectomy bed. Thus accurately identifying and delimiting the lumpectomy cavity boundaries is critical for all patients receiving breast irradiation.
The utility and significance of the invention disclosed here can be illustrated by the fact that in the USA alone approximately 200,000 women are diagnosed with breast cancer each year, leading to over 40,000 breast cancer related deaths per year. Usually, a breast cancer is detected as a lump within the breast tissue. The most common initial form of treatment is a lumpectomy, i.e., the surgical removal of the lump. Thereafter, all subsequent medical interventions are designed to reduce the risk of local disease recurrence. This, however, is a significant challenge. Both radiation therapy and pharmaceutical treatment (chemotherapy) have severe toxic effects and are less than 100% effective in preventing local disease recurrence. As will be outlined in more detail below, the invention disclosed here addresses some of the challenges associated with the prevention of local disease recurrence.
Specifically, in the case of a lumpectomy, the surgical procedure is often followed by radiation therapy to ensure that all remaining cancer cells are eliminated from the lumpectomy cavity. There are different modes of radiation therapies, but in each case, a key challenge is to focus the beam of high-energy radiation into the area of the original lumpectomy cavity and to reduce the exposure of healthy tissue to radiation. While this sounds simple, the delineation of the lumpectomy cavity is a significant practical problem even among radiation oncology experts. Therefore, a radio-opaque (i.e., X-ray visible) tissue void filler that can facilitate the detection and localization of the lumpectomy cavity would be an important advance in the treatment of early breast cancer.
Chemotherapy is an alternative to radiation therapy. But, the treatment of patients with chemotherapeutic agents is not without risks and exposes the entire body of the patient to a significant toxic burden. A significantly improved approach would be to provide the local delivery of appropriate chemotherapeutic agents directly to the site of the lumpectomy. While this approach would not necessarily protect the patient from the development of metastatic disease outside of the breast, the local delivery of chemotherapeutic agents directly into the lumpectomy cavity could have significant health benefits for early breast cancer patients.
Identical considerations apply to a host of post-surgical cavities requiring post-operative void filling and image-characterization. These include post-craniotomy cavities in the brain, post-prostatectomy cavities in the pelvis, and post-operative cavities in the thorax/lung, and the abdomen.